This invention relates to work reducing, typically the reduction by rolls, of billets to bars, bars to bars of smaller thickness, or rods to wire. The rolls may be composed of metal such as iron or steel, but of particular interest is work reducing in which the rolls are composed of metalloids of the tungsten carbide type. The expression "of the tungsten--carbide type" as used in this application means metalloids of all types including carbides of molybdenum, tantalum, niobium and others and also borides, silicides, nitrides and the like. In the interest of dealing in a concrete example to aid those skilled in the art in understanding this invention, this invention will be described as applied to the reduction of bars to bars of smaller cross section by oppositely acting rolls. This invention is applicable to reducing of work of other types and such other work reducing is within the scoe of this invention.
In reducing work the radial pressure applied between each oppositely acting roll and the work is high and the tangential friction force on each roll is correspondingly high. The resulting reactive torque between the roll and the arbor on which the roll is mounted is correspondingly high and under this torque the roll tends to rotate relative to the arbor. This invention has particular relationship to the suppression of this relative rotation and it is an object of this invention to suppress the rotation of the roll relative to the arbor.
U.S. Pat. No. 4,008,598, Purcupile et al, discloses work-reducing apparatus in which lateral pressure is applied to suppress relative rotation of rolls by deformation of a deformable membrane under continuously applied hydraulic pressure. This apparatus has performed highly satisfactorily serving to reduce work during many hours of operation. However, the membrane is subject to failure by reason of fatigue resulting from the repeated impacts of the rolls against the work and it is desirable to preclude such failure.
It has also been proposed, in accordance with the teachings of the prior art, that the lateral pressure to suppress relative rotation of the rolls be applied by a heavy Belleville spring which is precompressed by a press. This expendient has the disadvantage that it demands the use and availability of a massive press or machine tool of similar type. In addition, the spring tends to relax while in use.
It is accordingly an object of this invention to overcome the deficiencies of the prior art and to provide for suppression of the relative rotation of the reducing rolls without continuous supply of hydraulic fluid and without a deformable membrane or of any other component which, in use, may fail from fatigue or relaxation, and without the requirement of the availability of a massive press or any other costly machine. It is also an object of this invention to provide a method for achieving the above object and work-reducing apparatus for practicing this method. It is a further object of this invention to provide apparatus and a method for applying high pressure or high thrust to a body, which apparatus shall not require a deformable membrane or massive machine tool for applying the high pressure or high thrust to a body.